The object of the invention is an amphibious caravan. The caravan of the invention comprises a floating chassis with wheels and at least one cabin with a living compartment. The caravan also comprises a vehicle deck receiving a towing vehicle. The chassis comprises propulsion means suitable for movement on water.
Several solutions are known from the patent literature, relating to amphibious caravans of the type described above. Among others, FR 2 645 498 A1 discloses an amphibious caravan which may be supplemented by floating pontoons. These pontoons are designed to bear the towing vehicle. The towing vehicle serves at the same time as the driving power source of the complete floating unit. The power of the towing vehicle is transmitted to the driving paddle wheels by a conveyor mechanism. A disadvantage of this known solution is that the water-tight body of the floating chassis is separate from the pontoons bearing the vehicle. Thereby the power of the engine of the vehicle may not be transmitted to the back part of the chassis, or may be transmitted only via very complicated mechanisms, where the driving means could be realised effectively, e.g. by means of a marine screw. Therefore, the very ineffective paddle wheel must be used.
Large number of known solutions are devoted to self-propelling amphibious caravans, i.e. caravans without a towing vehicle. Such solutions are disclosed in the documents EP 0 085 384 A2, DE-OS 2 238 786 and DE 30 49 833 A1. These known solutions seek to enlarge a relatively small rolling caravan, which take up relatively little space on dry land, and try to enlarge the caravan on the water by folding it out and thereby achieving more space. In this respect it must be noted that an independent engine built into a caravan is rather costly. The known self-propelling caravans (motor home, wohnmobile) tend to cost twice as much as a traditional caravan (wohnwagen) with a similar size and equipment. This extra cost is recovered very slowly, or never, because a caravan is normally not used so much so that the relatively small savings attained by omitting a towing car should justify the extra cost for the permanent motor and the related necessary parts in the caravan.
If the amphibious caravan has no independent propelling means, the towing vehicle is necessary under any circumstances. However, the known caravans with the xe2x80x9cfoldingxe2x80x9d extension do not allow the water transport of the towing vehicle, and at the same time these foldable caravans find only a very limited use on land. Therefore, the caravan either must return to the towing vehicle, or another towing vehicle must be found if the caravan does not return to its original starting point. In any case, the freedom of movement of the user is limited. Beside, these known amphibious caravans are relatively bulky, large, and also heavy. Often, these Caravans are so large that only very powerful towing vehicles can be used for their transport on land.
Generally, it is a common disadvantage of the known solutions that the floating chassis of the caravans is not small enough for average drivers with an average car to tow them. If the caravan with a floating chassis is so small so that it may be towed conveniently, there is not room enough on the deck for the towing vehicle.
The document DE-OS 1 926 726 teaches a floating vehicle with a floating chassis and a deck designed for receiving the towing vehicle. The floating chassis is propelled by the vehicle on the deck by means of an appropriate transmission mechanism. The floating chassis is also provided with caterpillars for land movement, and these are also driven by the towing vehicle on the deck, i.e. the floating chassis has no engine on its own The description refers to a covered space on the deck suitable for living, but provides no details concerning the structure of this living space. Hence, this disclosure do not teach an amphibious caravan which would provide a convenient living space, but at the same time being small enough to be easily transportable on land, and at the same time being large enough to be able to transport its own towing vehicle on the water.
Therefore, it is an object of the present invention to provide an amphibious caravan with a simple mechanical construction, which, on one hand, is capable of transporting its own towing vehicle on the water, and on the other hand comprises a sufficiently large and convenient living compartment, and thirdly, its rolling chassis is sufficiently small so that it may be towed conveniently on road by an average, middle-category car. It is a further object to provide a towable amphibious caravan which is well balanced in case of different types of towing vehicles (front or rear wheel drive, front or rear engine), and allows the towing vehicle always to look towards the bow of the floating chassis. It is a further object to provide an amphibious caravan that is appropriately stable in water and on land, has good road characteristics during towing, and is simple in construction, avoiding the need for special materials or technical solutions. Especially, it is sought to provide the rolling and floating chassis of the caravan in a solid, unitary structure. This allows a strong construction, and the watertight sealing of the floating chassis, xe2x80x94which basically functions as a hull in the waterxe2x80x94is also much easier to realise.
Further, it was sought to create a caravan that is easy to handle in general.
According to the invention, the above goals are achieved with an amphibious caravan comprising a floating chassis with wheels and at least one cabin with a living compartment, and further a vehicle deck receiving a towing vehicle, the vehicle deck situated adjacent to the cabin, and further comprising propulsion means suitable for movement on water, in particular marine screw. According to the invention, at least one cabin is movable along the longitudinal axis of the chassis, so that the length of the deck receiving the vehicle is variable. With this solution it is ensured that the caravan constitutes a relatively short, compact unit on land, but it xe2x80x9cstretches outxe2x80x9d on water, and allows deck space for the towing vehicle. Because the cabin comprising the living compartment constitutes a unit with a weight commensurable to the weight of the towing vehicle, and being movable relative to the chassis, at the same time an optimal balance of the chassis may be achieved. This optimal balance is reached by slightly varying the displacement of the cabin, and as a result, the complete floating unit will float in a horizontal position even with cars of different size and weight. If the cabin would be in a fixed position on the aft of the chassisxe2x80x94as with the known solutionsxe2x80x94, the balance would have to be established with other known methods, like ballast water or similar. This would require additional complicated and expensive mechanical apparatus in the chassis. Contrarily, the caravan according to the invention needs no complicated structural elements, in particular there is no need for assembling the floating chassis from several separate parts, and thereby the sealing problems are eliminated. The floating chassis may be manufactured as a single unit, which may be made appropriately stiff and strong with known manufacturing methods. Also, the unit containing the living compartment need not be taken apart either, so the living quarters of the user need not be disturbed during launching or landing. Thereby the original purpose of the caravan, namely the rest and recreation of the users, may continue undisturbed. It must be stressed that the longitudinal translation of the cabin not only serves to increase the deck space, but also serves as a counterweight to establish the optimal balance of the whole floating unit on the water. This is especially advantageous in case of modem front-wheel driven cars, where the engine is normally in the front. As a result, the mass center of the car is also nearer the front, which negatively influences the balance of the chassis when the towing car is placed on the deck. The cars must be positioned before the cabin, and with the front towards the bow, if the amphibious caravan is driven from the car. This negative effect may be compensated well, practically perfectly, by pushing the cabin back. Therewith all types of cars may be placed before the cabin, with the front looking forward, and the amphibious caravan may be driven conveniently and safely from the seat of the car. With a preferred embodiment, the caravan of the invention is equipped with a drive mechanism co-operating with the undercarriage of the towing vehicle for utilising the power of the engine of the towing vehicle. With this solution an independent engine in the caravan is spared, saving cost and weight. Advantageously, the drive mechanism may be translated along the longitudinal axis of the chassis, and thereby being adjustable to the size and drive type of the driving vehicle. In this manner the towing vehicle may be placed optimally regarding the balance and mass center of the floating unit, and the front-wheel or rear-wheel drive of the towing vehicle may be considered as well. Therefore, the towing vehicle can always be placed on the floating chassis in a forward-looking position. This facilitates the operation of the engine, change of speed, etc. and the use of other navigation and comfort equipment which is installed in the towing vehicle. The complete floating unit may be driven from the driver""s seat of the car, even the steering of the floating unit may be done with the steering wheel of the car.
However, it is also possible to include a separate engine in the chassis. In this case a relatively low-power electric motor may be considered, powered by accumulators and/or solar cells. Gasoline, petrol or gas-fuelled combustion motors are also applicable. These engines may help to reach port even if the vehicle on the deck is unusable, or the towing vehicle is not onboard. E.g. a smaller electric motor is easily installed in the chassis, and the more complicated and less efficient mechanical transmission between the car and the propulsion means may be spared.
With an especially advantageous embodiment, the chassis comprises a towing mechanism extending from the chassis, and the cabin is movable along a rail system bearing on the towing mechanism. The rail system provides a stable support for the cabin in the displaced position, and facilitates the easy displacement and relocation of the cabin itself. Preferably, the cabin is guided along the rail system with self-adjusting roller pairs. This solution ensures a backlash-free and stress-free stable connection between the cabin and the guiding rail system. The fastening force is proportional to the weight of the cabin itself. With an especially advantageous embodiment, the displaced cabin is supported flexibly and adjustably on the towing triangle, e.g. by the up-turned backing wheel. The tipping of the cabin is prevented by chains attached to the bottom of the cabin and to the towing triangle.
With a further improved embodiment, the deck comprises sideways extendible raves. This provides a convenient walking deck on both sides of the vehicle, and raises the side walls of the floating chassis, thereby improving its safety. The very same removable raves may be used for the boarding of the towing vehicle, or facilitates the landing or launching of the amphibious caravan on swampy, moorish ground or beach.
Although the cabin may be moved by human force, it may be advantageous to provide a hydraulic or spring-action cylinder-piston pair on the chassis for facilitating the movement of the cabin. Alternatively, the cabin may be moved by an electric supplementary motor. Optionally, the wheels of the chassis may be at least partly retractable into the chassis. The hydrodynamic parameters may substantially improve in this manner. Alternatively, the wheels of the chassis may be dismounted in water.
A further preferred embodiment of the caravan comprises a retractable and extendible support wheel to facilitate landing and/or launching. A further possibility is the provision of a stabilising support leg for stabilising the caravan on land, preferably on the deck side of the chassis. The support wheel may serve as the reserve wheel of the car or the floating chassis. The role of the support wheel is to bear the weight of the towing vehicle during rolling (or towing) onto the deck of the amphibious caravan, and to take up a part of the weight on soft, swampy grounds, and to facilitate the landing and launching of the complete floating unit. These support wheels also serve to protect the chassis against bumps and collisions from the front or the side.
It is also preferred to place the marine screw and the rudder within the floating body, in a protected and surrounded water channel. Thereby it is easier to protect these sensitive parts during towing, landing or launching, or during the movement in water.